1. Field of the Invention
This invention relates to a method for the manufacture of a micro array, whereby surface areas of a chip are brought into contact with different aqueous solutions that contain at least one coating substance. The invention also relates to an apparatus to provide a chip for a micro array with aqueous substances that contain coating substances.
2. Description of the Prior Art
A method of this type for the manufacture of a micro array and an apparatus for the coating of a chip of a micro array are known from DE 101 32 761 A1. In that apparatus, a planar glass plate is used, the surface of which is structured so that it has hydrophobic and hydrophilic coating areas. Then, on the hydrophilic surface areas, small-volume aqueous probes in the range of picoliters to nanoliters are applied. For the positioning of the hydrophilic surface areas underneath the dispenser, the glass plate is moved relative to the dispenser. The construction of the dispenser is not described in any further detail in the above referenced unexamined application, although in practice it is customary for the deposition of biological or biochemical samples to use a nanoliter pipette that has a capillary filled with the aqueous solution, has a discharge opening on its one end and a piezoelectric actuator on its other end, by means of which the solutions in the capillary can be transported to the discharge opening, where they can be dispensed in the form of a microdrop. A nanoliter pipette of this type is described, for example, in T. Vo-Dinh et al., DNA Biochip Using a Phototransistor Integrated Circuit, Analytical Chemistry, Vol. 71, No. 2 (Jan. 15, 1999). The nanoliter pipette, however, has the disadvantage that as the drop separates from the discharge opening, the microdrop can be deflected slightly to the side. The microdrop can consequently land to one side of the surface area of the chip that is to be coated with the aqueous solution, where it becomes mixed on a neighboring surface area of the chip with a solution that is different from the original aqueous solution, or with another aqueous solution that will subsequently be applied. The danger of a mixing of this type is present particularly when the individual areas to be coated are located very close to one another so that as many fields as possible can receive different coatings on a chip with compact dimensions. However, the entire micro array is unusable if the chip is coated incorrectly in even one single location.
The object of the invention is therefore to create a method and an apparatus of the type described above that make possible a fast, simple and reliable deposition of the coating areas on the chip.